Molecular ecology of key organisms in sulfur and carbon cycling in marine sediments

The World s oceans host a variety of sulfidic habitats. Yet, microorganisms oxidizing reduced inorganic sulfur compounds have mostly been studied at hydrothermal vents, in anoxic basins, conspicuous microbial mats and symbioses but rarely in coastal sediments. In this thesis sulfur-oxidizing prokaryotes (SOP) of a eutrophic intertidal sand flat in the German Wadden Sea were investigated by molecular techniques. The diversity, abundance and activity of SOP were analyzed in particular among the Gammaproteobacteria. Comparative sequence analysis of the 16S rRNA and three genes involved in sulfur oxidation revealed a high diversity of mainly gammaproteobacterial SOP. Most of them were closely related to thiotrophic symbionts, including those of the tubeworm genus Oligobrachia. A group of free-living relatives accounted for up to 4% of all cells (~1.3 × 108 cells ml-1). Consistent with a presumed chemolithoautotrophic utilization of inorganic sulfur compounds, these and numerous other members of the Gammaproteobacteria incorporated 14CO2 as revealed by microautoradiography (MAR). The findings demonstrate that non-filamentous Gammaproteobacteria are important catalysts of sedimentary sulfur oxidation and contribute to CO2-fixation in coastal surface sediments. Similarly, Roseobacter clade bacteria (RCB) accounted for unexpectedly high abundances of up to 10% of all cells in surface sediments (~2.5 × 108 cells ml-1). A RCB-related genome fragment of 35 kb was recovered from a metagenomic fosmid library. It encoded genes of the SOX multienzyme system including the sulfur dehydogenase SoxCD, but also the complete rDSR pathway, a gene arrangement that is unique among SOP. Gene-targeted FISH confirmed the presence of the gene dsrA in sedimentary RCB enriched in anaerobic sulfidic medium. In addition, a novel gene, which encodes a putative dioxygenase, designated as dsrU, was identified in the rDSR pathway. Protocols were developed for application of MAR and nano-scale secondary ion mass spectroscopy (nanoSIMS) to marine sediment samples to follow assimilation of acetate in single cells. Members of the Gammaproteobacteria appeared to assimilate slightly more acetate than RCB, whereas sulfate-reducing bacteria showed no significant incorporation. Particularly the combination of flow cytometry and nanoSIMS proved to be powerful for up-scaling of the analysis of substrate uptake by sediment bacteria enabling an efficient, high-resolution profiling of single cells from complex microbial communities

Digital cinema or what happens to the dispositif?

Diffusé avec l’accord des Éditions Amsterdam University Press, détentrices des droits d’auteur sur ce texte.The digital cinema package : Created in 2005 by the Digital Cinema Initiatives—a group of Hollywood majors that formed a joint venture in 2002,—the Digital Cinema Package (DCP) is a wrapper containing images, sound, subtitles, and metadata. Six studios got together to agree on internationally valid norms (“DCI specifications”) to ensure that their movies would be screened in 2K / 4K and compressed in JPEG 2000. The initiative also strove to protect movies against copyright infringement and to assert total control over the movies’ distribution via a decryption code, the key delivery message (KDM), without which the encrypted content could not be accessed. The KDM is a rental license that allows projection under specific conditions. Theoretical framing : In this chapter, Frank Kessler and Sabine Lenk discuss the debate on the digitization of film and what the digital roll-out means for cinema and for the audience. With a particular focus on the transformations and continuities in what film theory commonly addresses as the traditional cinematic dispositif, Kessler and Lenk explore the positions taken by various authors participating in the debate and ask the question: To what extent is the cinematic dispositif actually affected by the shift from celluloid to digital

Filmpioniere (Sammelrezension)

Martin Sopocy: James Williamson. Studies and Documentsof a Pioneer of the Film NarrativeJoseph P. Eckhardt: The King of the Movies. Film PioneerSiegmund Lubin